Ordinary Clock Mode; Transparent Clock Mode - Lenovo ThinkSystem NE2552E Application Manual

Ordinary Clock Mode

Transparent Clock Mode

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NE2552E Application Guide for ENOS 8.4
PTP packets have a Control Plane Protection (CoPP) queue of 36. You cannot
change this CoPP priority. However, you can modify the PTP queue rate using the
following command:
NE2552E(config)# qos protocol-packet-control rate-limit-packet-queue
<0‐47> <1‐10000>
When the NE2552E Flex Switch is configured as an ordinary clock, it synchronizes
its clock with the master clock. If the NE2552E does not detect a master clock, it will
not synchronize its clock with any other device. In this mode, the NE2552E's clock
cannot be modified manually or using another time protocol such as Network
Time Protocol (NTP).
As an ordinary clock, the NE2552E synchronizes with a single PTP domain. The
switch uses a delay‐request mechanism to synchronize with the master clock. The
switch uses a source IP address for the packets it generates. You can create a
loopback interface for this purpose. By default, the switch uses the lowest interface
in the VLAN from which the sync messages are received. To assign a loopback
interface, use the following command:
NE2552E(config)# ip ptp source-interface loopback <interface number>
Note: If there are no interfaces on the switch that belong to the VLAN from which
the sync messages are received, then the ordinary clock will not function. An error
message will be generated. You can view this message using the following
command:
NE2552E# show ptp
When the NE2552E is configured as a transparent clock, its time can be set
manually or using any time protocol. You must configure PTPv2 for the
transparent clock to function. The switch does not modify PTPv1 packets as they
pass through the switch.
As a transparent clock, the NE2552E supports syntonization (synchronization of
clock frequency but not time) and synchronization with multiple domains.
Event packets received on all ports on the switch that have PTP enabled will be
adjusted with the residence time. The switch sends all PTP packets to the multicast
group address: 224.0.1.129. You can use Protocol Independent Multicast (PIM),
Internet Group Management Protocol (IGMP), or any other multicast protocol to
route the PTP packets.